Identify the missing restriction sites (A, B and C) in the given E. coli cloning vector pBR322.

A - BamH I; B - Cla I; C - Pst I

The correct answer is Option (1) → A - BamH I; B - Cla I; C - Pst I

pBR322 is indeed one of the first artificial cloning vectors developed in 1977 by Boliver and Rodriguez. It is a plasmid derived from Escherichia coli (E. coli) and has been widely used in genetic engineering experiments.

 E. coli cloning vector pBR322 showing restriction sites (Hind III, EcoR I, BamH I, Sal I, Pvu II, Pst I, Cla I), ori and antibiotic resistance genes (ampR and tetR). rop codes for the proteins involved in the replication of the plasmid.